G11 versus S90

VERSUS

I need your help.  On the eve of my nude photography class, I’m in camera mode again.  I was supposed to get the Canon G11, but a friend showed me her S90, which has the same processor and same sensor as the G11, only in a much more compact body.  Plus, although the S90 is just around 4k cheaper, the under water case for the S90 is about 10k cheaper.  But some say G11 is still a smidgen sharper and it has a little more zoom.  I need it mainly for underwater photography because the D10 can only go down about 30 feet deep.  But with diving, we often go beyond 100 feet.  I’ve been vacillating every hour with which one I should go for.  The bigger, slightly better specs G11 or the smaller, cheaper S90.  Even the articles I’ve read on the internet have given conflicted opinions on the matter.  Some say G11 is better, while others say S90 is the way to go.  So calling on anyone who might have either camera (or better yet those who’ve tried both!) to give  your comments and feedback so maybe I could make a more informed decision?  Camera buffs?  Canon employees?  Photographers?  Techies?  Anyone?  I’m so confused! Waaah!!!